Estimate the eye's accommodation amplitude by age (Hofstetter) and compare it with the measured near point.
Hofstetter 经验公式按年龄估算调节幅度区间，近点距离 = 100 / 调节幅度（cm），用于评估老花与调节不足。
| 年龄 | 最小幅度(D) | 平均幅度(D) | 近点(cm) | 说明 |
|---|---|---|---|---|
| 10 | 12.5 | 15.5 | 6.5 | 调节力强 |
| 20 | 10.0 | 12.5 | 8.0 | 调节力佳 |
| 30 | 7.5 | 9.5 | 10.5 | 开始下降 |
| 40 | 5.0 | 6.5 | 15.4 | 老视前期 |
| 50 | 2.5 | 3.5 | 28.6 | 老视明显 |
| 60 | 0.0 | 0.5 | 200 | 调节近丧失 |
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Hofstetter formulas | Minimum = 15 - 0.25 × (age - 10); mean = 18.33 - 0.30 × age; maximum = 25 - 0.40 × age | Hofstetter HW (1950), The amplitude of accommodation in presbyopia, Am. J. Optom. |
| Definition of accommodation amplitude | The maximum increase in ocular power achievable by accommodation | ISO 13666:2019, Ophthalmic optics - Vocabulary |
| Decline with age | Accommodation amplitude declines with age, the direct cause of presbyopia | Duane A. (1922), Studies in monocular and binocular accommodation |
| Presbyopia criterion | When residual accommodation cannot sustain near tasks comfortably, a near addition is required | ISO 13666:2019, Ophthalmic optics - Vocabulary |
基于 Hofstetter 公式根据年龄计算最小/平均/最大调节幅度与近点距离，评估调节功能。
调节幅度计算器，基于Hofstetter公式根据年龄计算最小/平均/最大调节幅度与近点距离。。医疗专业工具，基于权威医学标准，仅供参考。